package me.ZFC.demo;

public class Test4 {
    public static void main(String[] args) {
      StringBuilder sb=new StringBuilder("abc");
       sb.append(1);
       sb.append(2.3);
       sb.append(true);
        System.out.println(sb);
        sb.reverse();

        System.out.println(sb);
        System.out.println(sb.length());
    }
}
